[#3094] Checkpoint: added UTs, doc to do

Author: fxdupont

src/bin/dhcp4/dhcp4_messages.cc

@@ -174,6 +174,8 @@ extern const isc::log::MessageID DHCP4_SUBNET_SELECTED = "DHCP4_SUBNET_SELECTED"
 extern const isc::log::MessageID DHCP4_SUBNET_SELECTION_FAILED = "DHCP4_SUBNET_SELECTION_FAILED";
 extern const isc::log::MessageID DHCP4_TESTING_MODE_SEND_TO_SOURCE_ENABLED = "DHCP4_TESTING_MODE_SEND_TO_SOURCE_ENABLED";
 extern const isc::log::MessageID DHCP4_UNKNOWN_ADDRESS_REQUESTED = "DHCP4_UNKNOWN_ADDRESS_REQUESTED";
+extern const isc::log::MessageID DHCP4_V6_ONLY_PREFERRED_MISSING_IN_ACK = "DHCP4_V6_ONLY_PREFERRED_MISSING_IN_ACK";
+extern const isc::log::MessageID DHCP4_V6_ONLY_PREFERRED_MISSING_IN_OFFER = "DHCP4_V6_ONLY_PREFERRED_MISSING_IN_OFFER";
 
 } // namespace dhcp
 } // namespace isc
@@ -348,6 +350,8 @@ const char* values[] = {
     "DHCP4_SUBNET_SELECTION_FAILED", "%1: failed to select subnet for the client",
     "DHCP4_TESTING_MODE_SEND_TO_SOURCE_ENABLED", "All packets will be send to source address of an incoming packet - use only for testing",
     "DHCP4_UNKNOWN_ADDRESS_REQUESTED", "%1: client requested an unknown address, client sent ciaddr %2, requested-ip-address %3",
+    "DHCP4_V6_ONLY_PREFERRED_MISSING_IN_ACK", "v6-only-preferred option missing in 0.0.0.0 offer to query: %1",
+    "DHCP4_V6_ONLY_PREFERRED_MISSING_IN_OFFER", "v6-only-preferred option missing in 0.0.0.0 offer to query: %1",
     NULL
 };
 

src/bin/dhcp4/dhcp4_messages.h

@@ -175,6 +175,8 @@ extern const isc::log::MessageID DHCP4_SUBNET_SELECTED;
 extern const isc::log::MessageID DHCP4_SUBNET_SELECTION_FAILED;
 extern const isc::log::MessageID DHCP4_TESTING_MODE_SEND_TO_SOURCE_ENABLED;
 extern const isc::log::MessageID DHCP4_UNKNOWN_ADDRESS_REQUESTED;
+extern const isc::log::MessageID DHCP4_V6_ONLY_PREFERRED_MISSING_IN_ACK;
+extern const isc::log::MessageID DHCP4_V6_ONLY_PREFERRED_MISSING_IN_OFFER;
 
 } // namespace dhcp
 } // namespace isc

src/bin/dhcp4/dhcp4_messages.mes

@@ -1154,3 +1154,13 @@ contains the client and the transaction identification information.
 The second argument contains the IPv4 address in the ciaddr field. The
 third argument contains the IPv4 address in the requested-ip-address
 option (if present).
+
+% DHCP4_V6_ONLY_PREFERRED_MISSING_IN_ACK v6-only-preferred option missing in 0.0.0.0 offer to query: %1
+An DHCPACK for the 0.0.0.0 address was generated for a client requesting
+the v6-only-preferred (108) option but the option is not in the response as
+expected: the erroneous response is dropped, the request query is displayed.
+
+% DHCP4_V6_ONLY_PREFERRED_MISSING_IN_OFFER v6-only-preferred option missing in 0.0.0.0 offer to query: %1
+An DHCPOFFER for the 0.0.0.0 address was generated for a client requesting
+the v6-only-preferred (108) option but the option is not in the response as
+expected: the erroneous response is dropped, the discover query is displayed.

src/bin/dhcp4/dhcp4_srv.cc

@@ -2843,24 +2843,9 @@ Dhcpv4Srv::createNameChangeRequests(const Lease4Ptr& lease,
 bool
 Dhcpv4Srv::assignZero(Subnet4Ptr& subnet, const ClientClasses& client_classes) {
     Subnet4Ptr current_subnet = subnet;
+    // Try subnets.
     while (current_subnet) {
-        // Try pools.
-        for (auto const& pool : current_subnet->getPools(Lease::TYPE_V4)) {
-            if (!pool->clientSupported(client_classes)) {
-                continue;
-            }
-            auto const& co = pool->getCfgOption();
-            if (!co->empty()) {
-                OptionDescriptor desc = co->get(DHCP4_OPTION_SPACE,
-                                                DHO_V6_ONLY_PREFERRED);
-                if (desc.option_) {
-                    subnet = current_subnet;
-                    return (true);
-                }
-            }
-        }
-        // Try the subnet.
-        auto const& co = current_subnet->getCfgOption();
+        const ConstCfgOptionPtr& co = current_subnet->getCfgOption();
         if (!co->empty()) {
             OptionDescriptor desc = co->get(DHCP4_OPTION_SPACE,
                                             DHO_V6_ONLY_PREFERRED);
@@ -2875,7 +2860,7 @@ Dhcpv4Srv::assignZero(Subnet4Ptr& subnet, const ClientClasses& client_classes) {
     SharedNetwork4Ptr network;
     subnet->getSharedNetwork(network);
     if (network) {
-        auto const& co = network->getCfgOption();
+        const ConstCfgOptionPtr& co = network->getCfgOption();
         if (!co->empty()) {
             OptionDescriptor desc = co->get(DHCP4_OPTION_SPACE,
                                             DHO_V6_ONLY_PREFERRED);
@@ -3802,6 +3787,8 @@ Dhcpv4Srv::processDiscover(Pkt4Ptr& discover, AllocEngine::ClientContext4Ptr& co
         if (ex.getIPv6OnlyPreferred()) {
             if (!ex.getResponse()->getOption(DHO_V6_ONLY_PREFERRED)) {
                 // Better to drop the packet than to send an insane response.
+                LOG_ERROR(packet4_logger, DHCP4_V6_ONLY_PREFERRED_MISSING_IN_OFFER)
+                    .arg(discover->getLabel());
                 return (Pkt4Ptr());
             }
         }
@@ -3886,6 +3873,8 @@ Dhcpv4Srv::processRequest(Pkt4Ptr& request, AllocEngine::ClientContext4Ptr& cont
         if (ex.getIPv6OnlyPreferred()) {
             if (!response->getOption(DHO_V6_ONLY_PREFERRED)) {
                 // Better to drop the packet than to send an insane response.
+                LOG_ERROR(packet4_logger, DHCP4_V6_ONLY_PREFERRED_MISSING_IN_OFFER)
+                    .arg(request->getLabel());
                 return (Pkt4Ptr());
             }
         }

src/bin/dhcp4/dhcp4_srv.h

@@ -737,7 +737,7 @@ class Dhcpv4Srv : public process::Daemon {
     /// or assigning the zero address as the assigned address if the
     /// Yiaddr field of the DHCPv4 message header...
     ///
-    /// Check if there is a pool, subnet or shared network defining an
+    /// Check if there is asubnet or shared network defining an
     /// IPv6-Only Preferred option which will be included by the response.
     ///
     /// @param subnet Reference to the selected subnet, can be modified if